1. Field
Example embodiments of the present invention may relate to a method of monitoring equipment and, more particularly, to a method of forming standard information for defining a fault pattern of semiconductor manufacturing equipment and a method of monitoring semiconductor manufacturing equipment using the same.
2. Description of Related Art
Generally, a semiconductor device is manufactured by repeatedly and selectively performing a plurality of processes such as diffusion, deposition, exposure, etching, cleaning, etc. on a wafer. Semiconductor manufacturing equipment is used to perform each process.
The semiconductor manufacturing equipment for performing each process may generate a fault (e.g., error) while performing the process. Throughout the specification the term “fault” may be interchangeably used with “error.” When a fault is detected, the equipment may transmit fault data to a controller, which may display the fault state or the controller may generate an alarm. Accordingly, an operator may be notified of the fault and may correct the fault.
In a conventional fault monitoring method, faults generally detected by the monitoring method are divided into a plurality of fault groups, each of which has similar fault states.
The conventional monitoring method includes two steps, e.g., (1) a process of extracting fault patterns due to faults and storing the extracted fault pattern in a database, and (2) a process of recognizing the fault pattern.
FIG. 1 is a graph illustrating a conventional method of determining a fault pattern.
Referring to FIG. 1, FAULTS I to IV are fault pattern regions extracted in an offline state and distributed on a plane. Here, “plane” may mean a 2-D graphical representation. These fault regions are formed on the basis of received fault data from previously operated semiconductor manufacturing equipment. The fault pattern region information may be stored in a database.
The fault pattern generated by semiconductor manufacturing equipment may be recognized as follows. As shown in FIG. 1, when received (detected) data deviates from a normal management region, an operator determines whether the detected data is similar to fault pattern regions I to IV stored in the database. The similarity is determined based on a statistical distance between the received data and the fault pattern regions I to IV. Therefore, as the statistical distance increases between the received data and the fault pattern regions I to IV, similarity between the received data and the fault pattern region I to IV decreases.
However, when the received data is within any one boundary of the fault pattern regions I to IV, the operator determines that the fault of the received data corresponds to that fault pattern region. When the received data is not within any boundary of the fault pattern regions I to IV, the operator determines that a new fault may have been generated. At this point, the operator may take the semiconductor manufacturing equipment offline, and input a pattern for the new fault to the database. In the conventional monitoring method, because the new fault pattern is determined based on the statistical distance, there is a transition time for determining the new fault pattern.
In addition, determining whether any data received (detected) from the semiconductor manufacturing equipment is accurately included in any one of the fault pattern regions I to IV is difficult. Also, the determination through the proximity of the statistical distance may cause inaccurate definition of the fault pattern of the received data. Therefore, an operator who receives inaccurate defined fault patterns may perform the wrong correction on the semiconductor manufacturing equipment. For example, if a fault is incorrectly determined to have been caused by heat, increasing/decreasing the heat may cause further damage to a semiconductor device when the fault was really caused by lack of oxygen.